Gypsum wall board



June 2, 1931. G. NEW 1,803,003,

GYPSUM WALLBOARD FiledMay 20, 1929 INVENTOR 6057/! v5 ,4. NEW

TTORNEY Patented 0...... 2, 1931 UNITED STATES PATENT OFFICE GUSTAVE A.NEW, OF PORT CLINTON, OHIO, ASSIGNOR TO -AMERICAN GYTPSUM COM- -PANY, OFPORT CLINTON, OHIO, A CORPORATION OF OHIO GYPSUM .WALL BOARD Applicationfiled May 20,

This invention relates to improvements in gypsum wallboard, and moreparticularly to an improved gypsum wall covering material and processfor making the same.

In a previous application filed by me on March 26, 1928, Serial No.264.,658, which issued as Patent No. 1,787,163 December 30, 1930, Idisclosed a construction and process for manufacturing gypsum wallboardwherein the edges of the board were reinforced by a fabric strip whichwas folded into the desired cross-sectional contour and fed between theedges of the covering sheets during the proces of making the board, withthe result that one folded portion of the strip was embedded in theplaster body and other portions extended over the edge faces of theplaster and were sealed thereto by the penetration of the plasterthrough the meshes of the fabric.

The purpose of the present invention is to provide an improved producthaving woven fabric adapted to reinforce the edges as well as animproved method for folding and incorporating the folded material intothe board during the course of its manufacture, asa part of a continuousprocess, such as is now generally employed in the plaster boardindustry.

A further object of the invention is to provide plaster or wallboardwherein the fabric applied to the edges thereof assumes not only aT-form in sectional contour but is of double thickness throughout.

A further object of the invention is to provide a wallboard the edges ofwhich are reinforced by a strip of woven fabric so folded and appliedthat its edges are embedded in the plaster body of the wallboard.

A further object of the invention is to'provide a novel and practicalmethod of folding the reinforcing material into a so-called doubleT-form in which the edges of the unfolded reinforcing strip are broughttogether to form the base of the T and are thence fed into the edge ofthe board and embedded in the plaster or like material.

A preferred embodiment of my inviition is disclosed in the accompanyingdrawings, in which I v Figure 1 is a vertical cross section of one 1929.Serial No. 364,478.

edge portion of the finished board showing the disposition of thereinforcing material;

Figure 2 is a perspective view of a fragment of the finished productshowing more clearly the disposition of the edge reinforcing material.

- Figure 3 is a perspective view of a strip .Of reinforcingfabricshowing the successive steps in folding the strip from its initial toits final T-shape, and

Figures 4 to 8 are sectional views of the fabric strip taken at severalsuccessive points during the folding operation as indicated by lines l4to 8-8 respectively in Figure 3.

The following is a description of the product made in accordance with myinvention,

facturing the same.

As shown in Figures 1 and 2, the plaster or wallboard consists of acentral core or body 1 of plaster, i.' e., calcined gypsum or othersuitable material interposed between two covering sheets 2, 2 of fibrousmaterial preferably paper of the kind and quality generally employed forthe purpose. The two sheets are of the same Width and terminate flushwith the edge face of the plaster body 1, so that in the absence of edgereinforcing means, the product would have all of the characteristics .ofthe so-called raw or trowelled edge plaster board. The finished productmay be considered to be of an inch in thickness, which is the standardthickness for general purposes.

As already indicated, the edge faces of the plaster body are reinforcedby woven fabric in the form of a strip 3 which has been foldedlengthwise into T-form, the cross member portion 3a extending betweenthe covering sheets 2, 2 and perpendicular thereto, and the stem portion312' extending edgewise into the body 1, between the covering sheets 2,2.

Thereinforcing material, as folded, is of douthroughout both portions 3a1 should be treated with a suitable adhesive or sizing to give it acertain stiffness which will permit it to hold its shape better afterfolding and creasing. Due to its loosely woven 5 texture it follows thatit is capable of being intimately incorporated with the plaster body 1inasmuch as the plaster in its wet or plastic state can pass or beforced into the meshes of the fabric, thereby affording a secure bondbetween the two materials.

Referring now to a practical method of folding the fabric, Figures 3 to8 illustrate the 7 various steps or folding operations through which thefabric is carried in its progress from its original flat form to itsfinal T-shape. It will be understood in this connection, that thefolding of the fabric is a continuous operation carried on inconjunction with the manufacture of the plaster or wallboard on acontinuous process machine of any standard and approved design. To applymy reinforcing material such a machine could be equipped withanysuitable feeding and folding evices, although the apparatus preferablyused is that disclosed in a co-pending application filed by myself.

In Figure 3,the material may be assumed to advance from left to right,being fed or unwound from a roll and travelling in a substantiallystraight line toward the portion of the wallboard machine where the twocover sheets 2, 2 and the intermediate layer of wet plaster 1 passbetween pressure rolls and are reduced to the form of the finishedproduct.

The fabric leaves the roll as a flat strip, Figure 4, and preferably ina vertical plane. Immediately upon leaving the roll, it passes through asuitable folder which arches it transversely throughout its centralportion as 9 shown in Figure 5. The strip is then led into contact witha suitable forming block or mandrel having three faces arranged at rightangles to each other and around which the strlp is folded and creased,giving it the square U-shape shown in Figure 6. For con: venience theseveral portions of the strip may now be indicated by letters thus: abase portion a and two edge portions a, a of equal width, folded atright angles to the base portion a. Coacting with this block aresuitable pressure members which act to crease the strip of materialalong lines I), I), thus establishing the width of the cross portion ofthe T-section to be ultimately formed. On leaving the forming block thestrip, retaining its square U-shape, is led to another folding devicewhich firstbrings the outer margins of the edge portions a, a of theU-shaped strip together and bends the remaining edge portions towardeach other, forming a somewhat triangularly shaped section as shown inFigure 7 As the strip advances, the edge portions a, a of the strip aregradually brought go gether, the portions thereof adjacent the base abeing simultaneously folded inwardly and over upon the base a. 4

The edge portions a, a are now L-shaped and located in back to backrelation, thus providing a double thickness of the material throughoutthe entire cross section of the folded reinforcing strip as shown inFigure 8. All of the folds of the strip are finally creased so that thefolded strip will hold its T-shape.

Having completed the final forming and creasing of the strip, it is thenfed by means of suitable guides toward the pressure rolls of thewallboard machine and thence into position between the covering sheets2, 2 substantially at the point where they pass between said rolls. Thefolded strip 3 is disposed edgewise, with the cross portion 3a of the Tvertical and parallel to the plane of i the edge of the face of thewallboard and the stem portion 31) extending horizontally into the bodyof plaster.

It will be understood that both edges of the plaster board may betreated in the same manner by the feeding of two continuous strips intothe opposite side edges thereof.

This method of reinforcing the edges of plaster board or the like maybeused to reinforce the edges of any sheet or board, with or withoutcovering sheets, the body of which is composed of a setting or hardeningmaterial. It will be evident to, those skilled in the art that myT-shaped fabric reinforcing I strips may be used to reinforce the edgesof numerous types of sheets which are made by rolling plastic materialinto sheet form and allowing itto harden and therefore I do not limit myinvention to the specific type of sheet described in this specificationand illustrated in the drawings.

Having set forth a preferred embodiment of my invention, I claim:

1. A wallboard comprising a plaster body, covering sheets on oppositesides of said body, and a strip of vwoven material folded in T- sectionof double thickness and applied along the edges of said bddy, with aportion thereof embedded edgewise in the body.

2. A wallboard comprising a plaster body, covering sheets on oppositesides of said body, and a strip of wovenmaterial folded lengthwise intoangularly disposed portions of double thickness and applied to'the edgeportions of the body so that said strip of woven material is embedded insaid body.

3. A wallboard comprising a plaster body, covering sheets on oppositesides of said body and terminating at the side edges thereof, and astrip of woven reinforcing fabric folded lengthwise upon itself to formportions of double thickness arranged in T-form, one portionbeingapplied parallel to the edge face of said body and the pther portion atright angles to said edge face.

45 consisting of advancing continuous sheets of covering sheets onopposite sides of said b and terminat ng at the edge faces thereof, anda strip of woven fabric folded upon itself 4. A wallboard comprising aplaster bodiy, y

to form portions of double thickness arranged in T-form, one portionbeing positioned in said plaster body parallel to the edge face of saidbody substantially flush with the edges of the covering sheets and theother portion extending into said-body at right angles to terial towardthe edgesof the board, folding the advancing strip longitudinally intoportions of double thickness arranged in T-form, and guiding the foldedstrip into the edge of the board.

6. A process of reinforcing the edges of gypsum wallboard in the courseof manufacture, consisting of feeding a strip of woven fabric towardtheedges of the board, folding the advancing strip longitudinally intoangularly. disposed portions of doublethickness of the material, andfeeding the folded strip into the edge of the board with one fportionparallel to the edges of the body 0 the board and'the other portionextending edge- 0 wise into said body.

7. A process of manufacturing wallboard consisting of advancingcontinuous sheets of covering material toward a pair of pressure rolls,feeding wet plaster between sald sheets in advance of said pressurerolls, feedin strips of edge reinforcing material towar the edges ofsaid ddvancmg sheets, folding said strips lengthwise into portions ofdouble. thickness and arranged in T-form, and- 40 guiding the foldedstrips between the edges of thecovering sheets with one portion embeddedparallel to the edge face 0 the plaster and the other portion embeddededgewise therein. 7.

8. .A process of manufacturing wallboard covering material toward a pairof pressure rolls, feeding wet plaster between said sheets in advance ofsaid pressure rolls, advancing a continuous strip ofwoven fabric towardthe edges of said advancing sheets, folding the strip lengthwise intoU-form, and thence into T-form, and guiding the folded strip between theedges of the advancing covering sheets with oneportionreinforcing theedge face of the plaster and the other portion embeddededgewisejtherein.

9. A process of manufacturing wallboard consisting of advancingcontinuous sheets of covering material toward 'a pair of. pressure theU-shaped strip into T-shape and creasing the same along the fold lines,and feeding the T-shape strip intothe edge of the advancing cover sheetsand wet plaster.

10. A process of manufacturing wallboard consisting of advancingcontinuous sheets of covering material toward a pair of pressure rolls,feeding wet plaster between said sheets in advance of said pressurerolls, feeding strips of fabric toward the path of the edges of saidadvancing sheets, longitudinally into a creasing the same along the foldlines, thence folding and'creasin the edge portions of the U-shapedstrip to orm angularly disposed folding the strip portions of doublethickness arranged in T'- form, and feeding the strip thus foldedbetween the edge of the advancing cover sheets with the cross portionofthe T-shape strip 'reinforcing the edge face of the plaster and thestem portion extending edgewise into the plaster.

In testimony whereof I hereunto aflix my signature this 10th day of May,1929. I GUSTAVE A. NEW.-

rolls, feeding wet plasterbetween said sheets in advance of saidpressure rolls, feeding strips of fabric toward the path of the edges 7of said advancing sheets, folding the strip longitudinally into .U-form,thence folding square U-form and

